Why we cry: studying a most human trait

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We expect babies and children to cry, but U.S. House Speaker John Boehner’s well-chronicled weepiness is a reminder that adults (including menfolk) shed plenty of tears, too.

Grief, personal conflict, and feelings of inadequacy are among the main reasons, but grown-ups also fill buckets at weddings, graduations and reunions because they are so happy.

Having a good cry every now and then may not be a bad idea. But crying too easily — or for no apparent reason — can be a symptom of brain damage from a neurological condition like amyotrophic lateral sclerosis (Lou Gehrig’s disease) or multiple strokes.

Crying is a big topic in scientific research today. Here’s a quick rundown on three areas of investigation.

Crying and tears

Other animals whimper in distress, but humans are believed to be the only species wired so that strong emotions provoke the shedding of tears. Dr. William H. Frey II, an Alzheimer’s researcher in St. Paul, Minn., who has studied tears as a sideline, reported in the early 1980s that tears provoked by emotion contain higher levels of proteins and the mineral manganese than the normal teary fluid that protects and lubricates our eyes.

Earlier this year, Israeli researchers reported results in the journal Science that suggested tears are capable of sending chemical signals.

They conducted an experiment that involved having men sniff both women’s tears (collected from women who watched sad movies) and a saline solution.

They couldn’t distinguish between them by smell, but other tests showed that the men reacted differently to a whiff of the real tears. Their testosterone levels dipped, and brain scans showed less activity in areas associated with sexual arousal. The researchers’ theory: women’s tears may counteract men’s aggressive tendencies.

Others, including Darwin himself, have speculated on the role of tears in evolution and natural selection. Tears, it has been said, are a clear signal of vulnerability, so they may have helped create emotional bonds that kept human communities together and therefore conferred some reproductive advantages.

Crying to feel better

Strong emotions bring on crying, but crying also often seems to release built-up stress and tension. The notion that crying may have a beneficial cathartic effect goes back to the Greeks and Romans, and Freud wrote about a large part of an emotion disappearing if it’s expressed.

Numerous surveys and questionnaire-based studies show people believe they feel better after crying — and not just in this country.

Half of the respondents in a large international study (4,200 young adults from 30 countries) reported that they felt better mentally after crying, compared with how they felt beforehand. About 40 percent felt the same, and the remaining 10 percent felt worse.

However, when researchers have studied crying in a laboratory setting, using sad movies to elicit tears (they call them tearjerkers for a reason), they’ve found just the opposite: Criers feel worse, not better, than noncriers exposed to the same stimulus.

There are any number of explanations for the inconsistency. People may feel bad right after crying, when lab measurements are made, but better about the episode as time goes on, particularly if beliefs about the benefits of “having a good cry” are widely held.

But perhaps the best and most obvious explanation for the discrepancy is that crying outside a lab setting is often done in a social context, and if other people respond with comforting words and gestures, we end up with some psychological reward for our tears.

Indeed, in the international survey, about 40 percent of the respondents were comforted when they cried, and as one might expect, that response was associated with a feel-good cry.

Of course, the reaction isn’t always positive. And crying can bring on shame. Many people hold back their tears until they’re alone. In the international survey, 35 percent of the respondents reported crying alone and 31 percent with one other person present.

Several years ago, Dutch researchers reported that the heart rates of 60 study subjects increased as they watched cry-eliciting movies, but then subsided after they started to cry. It seems that there’s a handoff from fight-or-flight arousal to parasympathetic calming, which is certainly how many of us experience crying.

Crying and depression

Depression makes people sad, so it’s presumed that depressed people cry more than those who aren’t depressed. There’s also an abiding belief that more severe bouts with depression can have just the opposite effect and rob people of their capacity to cry.

Neither proposition seems farfetched, but researchers who have scoured the published studies say there’s actually little evidence to support them.

A small study conducted several years ago to begin filling the void suggests, though, that the conventional wisdom may not be too far off the mark (although it is just one small study).

The 44 study subjects with mood disorders (dysthymia, adjustment disorder with depressed mood, major depressive disorder) were, in fact, more prone to crying than 132 people in a comparison group. At the same time, the researchers found that an inability to cry was associated with severe depression.

Many of the standardized questionnaires used to measure depression have questions about crying. Some researchers have raised the interesting question whether relying on crying as a sign of depression results in an underestimation of depression among men (who don’t, John Boehner notwithstanding, cry as often as women).

Rather than weep, depressed men may become aggressive and irritable. Yet, at least in this one small study, the gender imbalance seemed to even out, and men and women with mood disorders were equally prone to crying.

© 2011 President and fellows of Harvard College. All rights reserved. Distributed by Tribune Media Services, Inc.